抄録
The volcanic ash soils which passed through 0.5 mm. sieve, were treated with the normal potassium salt solutions of nitrate, sulphate acetate, oxalate and citrate, varying respectively in pH ; and the phosphosphoric acids thus dissolved, were destermined with the filtrates. The pH values of the filtrates were also estimated. The results were as follows : l. The amounts of P_2O_5 dissolved, varied with the pH of the salt solutions, but the tendency was markedly differred with the nature of soils. 2. The amounts of P_2O_5 also varied with the kinds of salt solutions, and the tendency was also differred with the nature of soils.
